Serum anti-Streptococcus pneumoniae antibody levels 10 days after immunization with heat-killed S. pneumoniae (HKSP) vaccine. Offspring were immunized with HKSP as described and subtype-specific anti-HKSP antibody assays were performed using serum harvested 10 days after immunization. Anti-PC (A and B) and anti-PspA (C and D) antibody was quantified using an ELISA technique (see Materials and Methods), which measured HKSP-specific subtype antibodies. The averages (bars) and SEM for each antibody subtype are shown and the numbers of mice (and the number of litters they were derived from) appear in columns in Supplementary Table 3. Values significantly different between the control animals and the atrazine-exposed animals at p ≤ .05 are designated by an asterisk.